Continuous lead strip casting line, caster, and nozzle

ABSTRACT

In one embodiment, a lead strip caster for battery grids includes a nozzle, a pair of rollers, and a molten lead supply to the nozzle. The lead strip caster produces a continuous lead strip for making battery grids. The nozzle has at least one passage that communicates with generally opposed faces of the nozzle at least partially received between the rollers to supply molten lead to exterior surfaces of the corotating rollers to form a continuous solid strip of lead from which battery grids may be made.

REFERENCE TO CO-PENDING APPLICATIONS

This is a continuation-in-part of U.S. patent application Ser. No.15/703,330 filed on Sep. 13, 2017 and priority U.S. Provisional PatentApplication No. 62/394,561 filed on Sep. 14, 2016 each of which isincorporated herein by reference in its entirety.

TECHNICAL FIELD

This disclosure relates generally to lead-acid battery manufacturingequipment, and more particularly to continuous lead strip casting lines,casters, and nozzles for battery plate grids.

BACKGROUND

Lead-acid batteries are a common energy storage device, and are oftenused in the automotive industry, marine industry, motive power industry,renewable energy industry, and uninterruptable power supply industry, aswell as other applications. Among other components, lead-acid batteriesinclude positive and negative plates that are installed in its interiorand are made of lead or lead alloy grids with an electrochemicallyactive battery paste material applied on the grids. The grids arecommonly designed to have intersecting wires defining open spaces toreceive the battery paste material.

Manufacturing grids for use as positive plates requires a certain amountof care, as the positive plates will ultimately include active materialin the form of lead dioxide (PbO₂) when charged and lead sulfate (PbSO₄)when discharged. Unlike negative plates, the half-cell potential of thepositive plates exists within a range where the positive plate grids canbecome oxidized during normal operation, which can result in corrosionon the grids and ultimate degradation of battery performance and evenbattery failure. As such, the positive plate grids are manufactured inspecific processes that yield a grain structure resistant to corrosion.The positive plate grids are typically produced by gravity casting,which can be a slow and laborious process, or by a continuous castingand rolling process that involves a casting machine that turns moltenlead into a hardened elongate continuous strip that is subsequentlypunched into individual grids connected together.

Conventional casting machines draw molten lead from an open pool that isexposed to one or more casting surfaces of one or more rollers. Leadimpurities, along with dross that develops from the oxidation of alloymaterials exposed to the atmosphere, residing at a top surface of themolten lead pool can be drawn into the cast strip during the process.The impurities can result in deformations and defects in the hardenedstrip of grids that are often magnified and intensified amid rolling.The deformations and defects, if present in the grid wires, canultimately degrade battery performance and shorten the battery's usefullife.

SUMMARY

One embodiment of a lead strip caster for battery plate grids mayinclude a ladle, a nozzle, a first roller, and a second roller. Theladle may have an inlet to receive molten lead and may have an outlet.The nozzle may have a passage that communicates with the outlet of theladle in order to receive molten lead from the ladle. The first rollermay be situated at a first exterior side of the nozzle. The first rollermay rotate via a first driver, and may have a first outer surface. Thesecond roller may be situated at a second exterior side of the nozzle.The second roller may rotate via a second driver, and may have a secondouter surface. During use of the lead strip caster, molten lead exitingthe passage of the nozzle may come into contact with the first outersurface of the first roller and may come into contact with the secondouter surface of the second roller. The molten lead may progressivelyharden as it moves downstream of the passage.

One embodiment of a lead strip caster nozzle may include a first passagereceiving molten lead, a second passage receiving molten lead, a firstexterior working surface, and a second exterior working surface. Thefirst exterior working surface may confront a first roller outersurface. The second exterior working surface may confront a secondroller outer surface. During use of the lead strip caster nozzle, moltenlead exiting the first passage may be delivered to the first exteriorworking surface, and molten lead exiting the second passage may bedelivered to the second exterior working surface.

One embodiment of a lead strip caster for battery plate grids mayinclude a nozzle, a first roller, and a second roller. The nozzle mayhave a first passage, a second passage, a first exterior workingsurface, and a second exterior working surface. The first roller mayhave a first outer surface that confronts the first exterior workingsurface in assembly. The second roller may have a second outer surfacethat confronts the second exterior working surface in assembly. Duringuse of the lead strip caster, molten lead exiting the first passage isdelivered to the first exterior working surface and comes into contactwith the first outer surface, and molten lead exiting the second passageis delivered to the second exterior working surface and comes intocontact with the second outer surface.

One embodiment of a lead strip caster for battery grid plates mayinclude a molten lead delivery system, a nozzle, a first roller and asecond roller. The molten lead delivery system may include a pump forsupplying molten lead to a shoe supplying molten lead to a nozzle. Amolten lead flow straightener may be disposed between the shoe and thenozzle. The nozzle may have one or more passages that communicate withthe shoe to receive molten lead and supply it to first and secondrollers adjacent opposite exterior sides of the nozzle and with outersurfaces which may come into contact with molten lead exiting the nozzlewhich lead may progressively harden as it moves downstream of the nozzleduring operation of the lead strip caster. The nozzle may include firstand second passages each receiving molten lead from the shoe anddischarging it between and into contact with outer surfaces of the firstand second rollers which lead may progressively harden into a solidstrip of lead as it moves downstream of the nozzle.

BRIEF DESCRIPTION OF THE DRAWINGS

Objects, features, and advantages of the present disclosure will beapparent from the following detailed description of exemplaryembodiments and best mode, appended claims, and accompanying drawings inwhich:

FIG. 1 is a schematic depiction of an embodiment of a continuous leadstrip casting line;

FIG. 2 is a perspective view of an embodiment of a lead strip caster forbattery plate grids;

FIG. 3 is perspective view of an embodiment of a ladle of the lead stripcaster;

FIG. 4 is a front view of the ladle;

FIG. 5 is sectional view of the ladle;

FIG. 6 is a perspective view of an embodiment of a nozzle of the leadstrip caster;

FIG. 7 is a perspective view of a one-half segment of the nozzle;

FIG. 8 is a side view of the nozzle;

FIG. 9 is a sectional view of the nozzle;

FIG. 10 is a sectional and partial view of the nozzle and of embodimentsof a pair of rollers of the lead strip caster;

FIG. 11 is front view of an embodiment of a flow straightener of thenozzle;

FIG. 12 is a perspective view of an embodiment of a roller of the leadstrip caster;

FIG. 13 is a partially sectional view of the roller;

FIG. 14 is a schematic perspective view of a molten lead delivery systemof a lead strip caster for battery plate grids;

FIG. 15 is an enlarged end view of a shoe and flow straightener of thesystem of FIG. 14 mounted on a nozzle of a lead strip caster;

FIG. 16 is an enlarged sectional view taken on line 16-16 of FIG. 14;

FIG. 17 is a view of the front face of the shoe;

FIG. 18 is a sectional view taken on line 18-18 of FIG. 17;

FIG. 19 is a view of the front face of the flow straightener; and

FIG. 20 is a sectional view of the flow straightener taken on line 20-20of FIG. 19.

DETAILED DESCRIPTION

Referring in more detail to the drawings, a lead strip caster 10 isdesigned and constructed to produce a continuous lead strip moreeffectively and more efficiently than previously possible. Thecontinuous lead strip produced by the lead strip caster 10 is intendedfor use as battery positive plate grids and can be subsequently punchedand processed therefor. Among many potential advancements, the leadstrip caster 10 possesses a smaller overall machine footprint to satisfyfloor space demands; impurities and dross residing in molten lead poolsare precluded from making their way into the produced lead strip; moltenlead flow and movement is more effectively controlled as it travelsthrough the lead strip caster 10; and adjustments to strip width andstrip thickness are more readily made. The lead strip caster 10 can beused in larger processes that manufacture lead-acid batteries for cars,trucks, hybrid vehicles, motorcycles, boats, snowmobiles, golf carts,consumer equipment such as powered wheelchairs, industrial equipmentsuch as forklifts and robots, and for other applications. As an aside,and as used herein, the term downstream generally refers to a directionthat is with the flow of molten lead as it moves through the lead stripcaster 10, the term upstream generally refers to a direction that isagainst the flow of molten lead as it moves through the lead stripcaster 10, the terms horizontal and vertical are used with generalreference to the ground surface upon which the lead strip caster 10 isstationed for operation, and the term lead refers to both lead and leadalloy materials.

In general, the lead strip caster 10 is but one piece of equipmentemployed in a larger process to produce continuous lead strips.Referring to FIG. 1, a continuous lead strip casting production line 12can also be equipped with furnaces 14, a set of rolling mills 16, anedge trim cutter 18, a tensioner 20, and a reeler 22, as well as othercomponents. The continuous lead strip casting production line 12 of FIG.1 is but one embodiment, and other embodiments of continuous lead stripcasting production lines could include more, less, and/or differentequipment than depicted and described. Additional processes downstreamof the continuous lead strip casting production line 12 may includepunching, pasting, cutting, drying, curing, and/or forming.

The lead strip caster 10 receives molten lead fed from the furnaces 14,and transforms the molten lead into a hardened continuous lead stripthat is advanced to the set of rolling mills 16 for further processing.At this stage in the process, the continuous lead strip has yet to beimparted with intersecting wires and open spaces. The lead strip caster10 can have various designs, constructions, and components in differentembodiments depending upon—among other considerations—the desired sizeof the produced continuous lead strip, the desired run rate of thecontinuous lead strip through the continuous lead strip castingproduction line 12, and preceding and subsequent steps in the largerproduction process. In the embodiment depicted in FIG. 2, the lead stripcaster 10 includes a frame 24, a ladle 26, a nozzle 28, a first roller30, a second roller 32, a first driver 34, and a second driver 36. Theframe 24 provides a structural skeleton for the lead strip caster 10 andsupports other components of the lead strip caster 10. The frame 24 canbe made up of many vertical, side, and cross members of steel that arejoined together.

Referring to FIGS. 3-5, the ladle 26 receives molten lead fed suppliedto it from the furnaces 14, and provisionally holds the molten lead in apool A as the molten lead continues on to the nozzle 28. With respect tothe flow and movement of the molten lead, the ladle 26 is configuredupstream of the nozzle 28. The ladle 26 can have various designs,constructions, and components in different embodiments. In theembodiment presented in FIGS. 3-5, the ladle 26 is constructed of fourside walls 38 and a bottom wall 40 that together define an interior 42to contain molten lead. The ladle 26 has an open top 44 and a closedbottom 46. The ladle 26 can, though need not, include a partition wall48 located within the interior 42 and spanning from one side wall 38across to another side wall 38, thereby dividing the interior 42 into afirst interior compartment 50 and a second interior compartment 52. Asmolten lead makes its way through the interior 42 from the firstinterior compartment 50, over the partition wall 48, and to the secondinterior compartment 52 along a path B, degasification of the moltenlead may occur. In this way, the partition wall 48 serves to retard themovement of the molten lead as the molten lead proceeds through theladle 26. An inlet 54 of the ladle 26 serves as the entrance throughwhich molten lead enters the interior 42 from the furnaces 14. The inlet54 is located at a bottom section and bottom half of the ladle 26 andjust above the bottom wall 40, as shown best in FIG. 5. Its locationfeeds molten lead from the inlet 54 directly to the first interiorcompartment 50. Furthermore, an outlet 56 of the ladle 26 serves as theexit through which molten lead leaves the interior 42 to the nozzle 28.Like the inlet 54, the outlet 56 is located at the bottom section andbottom half of the ladle 26 and just above the bottom wall 40, as shownin FIG. 5. Its location receives molten lead directly from the secondinterior compartment 52. As illustrated in FIGS. 3 and 4, the outlet 56has a slot-like shape in order to accommodate and match a correspondingentrance of the nozzle 28.

Referring to FIGS. 6-9, the nozzle 28 receives molten lead from theladle 26 and controls the flow and movement of the molten lead fordownstream delivery to the first and second rollers 30, 32. With respectto the flow and movement of the molten lead, the nozzle 28 is configureddownstream of the ladle 26. The nozzle 28 can have various designs,constructions, and components in different embodiments. In theembodiment presented in FIGS. 6-9, the nozzle 28 is made up of two-piecebody halves with a first body segment 58 and a second body segment 60that are bolted together in assembly, though the nozzle 28 could be madeof a single one-piece construction in other embodiments. For the flowand movement of molten lead through its body, the nozzle 28 has a firstpassage 62 and a second passage 64 in this embodiment; still, in otherembodiments the nozzle could have other quantities of passages such as asingle passage. The exact quantity of passages and their design can bedictated by the desired thickness of the continuous lead strip departingthe first and second rollers 30, 32, and the desired flow rate of moltenlead passing through the lead strip caster 10. For instance, in thisembodiment, it was found through computational fluid analysis andexperimentation that a pair passages promoted and facilitated improvedmolten lead fluid flow behavior compared to a single passage. Withoutwishing to be confined to a particular theory of causation, it isbelieved that the greater reduction in thickness observed in the singlepassage tended to cause an undesirable degree of irregular molten fluidflow behavior, or turbulence, within the single passage, whichconsequently hindered the flow of molten lead therethrough.

The first passage 62 is defined by inside surfaces of the nozzle's bodyand extends through the body from a first entrance 66 to a first exit68. Likewise, the second passage 64 is defined by inside surfaces of thenozzle's body and extends through the body from a second entrance 70 toa second exit 72. The first and second passages 62, 64 extendtransversely across the nozzle 28 between a first side wall 74 and asecond side wall 76, and short of the overall transverse length of thenozzle 28—the transverse length of the passages 62, 64 equates to thewidth of the produced continuous lead strip. The first and secondentrances 66, 70 reside at an entrance end 78 of the nozzle 28 that canbe mounted with the ladle 26 adjacent the outlet 56 so that the firstand second entrances 66, 70 fluidly communicate with the outlet 56 andreceive molten lead therefrom. The first and second entrances 66, 70 canhave slot-like shapes to match the shape of the outlet 56. Still, inother embodiments the first and second passages 62, 64 can share acommon entrance in the nozzle 28 that branches off downstream intoseparate passages. At the first exit 68, the first passage 62 terminatesopenly to a first working surface 80 (subsequently described) anddelivers molten lead thereto. Similarly, at the second exit 72, thesecond passage 64 terminates openly to a second working surface 82(subsequently described) and delivers molten lead thereto. In otherembodiments not depicted in the figures, the first and second exits 68,72 need not necessarily terminate directly and immediately at therespective first and second working surfaces 80, 82, and instead couldterminate openly to other locations of the nozzle such as at a locationupstream of the respective working surface.

With the exception of the site of flow straighteners (subsequentlydescribed) in some embodiments, the first and second passages 62, 64 canpossess a uniform and constant size and dimension from their entrances66, 70 and to their exits 68, 72. Further, the first and second passages62, 64 can have the same size and dimension relative to each other. Thefirst and second passages 62, 64 can be designed to follow a routethrough the nozzle 28 that promotes and facilitates laminar fluid flowtherethrough, and subdues turbulent fluid flow. For example, andreferring particularly to FIGS. 7 and 9, in this embodiment the firstand second passages 62, 64 have routes that mirror each other andinitially exhibit a first linear and parallel section C, then exhibit adivergent section D, and lastly exhibit a second linear and parallelsection E. The first linear and parallel section C begins at theentrances 66, 70 and spans straight therefrom with the first and secondpassages 62, 64 remaining parallel with each other until the divergentsection D. At the divergent section D, the first and second passages 62,64 take a sweeping and curved route, and deviate outboard away from eachother. And at the second linear and parallel section E, the first andsecond passages 62, 64 span straight to the exits 68, 72 and remainparallel with each other throughout. Still, in other embodiments thefirst and second passages 62, 64 could follow routes different thanthose presented here, and still effectuate suitable fluid flow.

As mentioned, in some embodiments the nozzle 28 may include flowstraighteners to promote and facilitate laminar fluid flow through thenozzle 28 and subdue turbulent fluid flow. The flow straighteners canhave various designs, constructions, quantities, and locations indifferent embodiments. In the embodiment presented in FIGS. 7-9 and FIG.11, a first flow straightener 84 is disposed in the first passage 62,and a second flow straightener 86 is disposed in the second passage 64.To accept the flow and movement of molten lead therethrough, the firstflow straightener 84 is located downstream of the first entrance 66 andupstream of the first exit 68, and at the second linear and parallelsection E; other locations are possible. The first flow straightener 84spans across the full transverse length of the first passage 62. At itslocation, the first passage 62 can have an increased size and dimensioncompared to its remaining extent in order to accommodate placement ofthe first flow straightener 84. Likewise, to accept the flow andmovement of molten lead therethrough, the second flow straightener 86 islocated downstream of the second entrance 70 and upstream of the secondexit 72, and at the second linear and parallel section E; otherlocations are possible. The second flow straightener 86 spans across thefull transverse length of the second passage 64. At its location, thesecond passage 64 can have an increased size and dimension compared toits remaining extent in order to accommodate placement of the secondflow straightener 86. The first and second flow straightener 84, 86 canbe of different types. Referring particularly to FIG. 11, in thisexample the flow straighteners 84, 86 are of the honeycomb type withmultiple ducts 88 through which molten lead flows.

To manage the temperature of molten lead flowing and moving through thenozzle 28 as the molten lead makes its way from entrance to exit, insome embodiments the nozzle 28 may include heaters. The heaters can havevarious designs, constructions, quantities, and locations in differentembodiments. In the embodiment presented in FIGS. 6-9, a total of eightheaters 90 are carried internally in the nozzle's body. The heaters 90can be positioned relative to the first and second passages 62, 64 inorder to generate more heat in the nozzle's body and to the molten leadmore immediately downstream of the entrances 66, 70, as compared to theheat generated more immediately upstream of the exits 68, 72. The moltenlead can hence experience a gradual reduction in temperature from itsentrance in the passages 62, 64 to its travel to the exits 68, 72. Theheaters 90 can be of different types. In one example the heaters 90 canbe cartridge-type heaters. Furthermore, it has been found that havingthe pair of passages 62, 64 in some cases can aid the temperaturemanagement capabilities and effectiveness of molten lead compared to asingle passage; the pair of passages presents reduced volumes andamounts of molten lead than a single passage, making it easier to impartheat thereto as desired.

Referring now particularly to FIGS. 6 and 7, at the exterior of thenozzle 28 and downstream of the passage exits 68, 72, the nozzle 28 hasthe first working surface 80 and the second working surface 82. Duringuse of the lead strip caster 10, the first working surface 80 receivesdelivery of molten lead from the first passage 62 at the first exit 68,and the second working surface 82 receives delivery of molten lead fromthe second passage 64 at the second exit 72. The molten lead flows andmoves downstream of the first and second exits 68, 72 and along thefirst and second working surfaces 80, 82 and to an egress end 92, wherethe two streams of molten lead merge together and unite between thefirst and second rollers 30, 32. In this embodiment, the first andsecond working surfaces 80, 82 resemble concave depressions defined byarcuately-shaped surfaces. The working surfaces 80, 82 are shapedcomplementary to outer surfaces of the roller 30, 32 so that the firstroller 30 can nest in the first working surface 80 with a clearancemaintained therebetween to accept delivery of molten lead, and so thatthe second roller 32 can nest in the second working surface 82 with aclearance maintained therebetween to accept delivery of molten lead. Oneexample of the nesting between the rollers 30, 32 and the workingsurfaces 80, 82 of the nozzle 28 is illustrated in FIG. 10. Similar tothe passages 62, 64, the working surfaces 80, 82 span transverselyacross the nozzle 28 between the first and second side walls 74, 76,where the side walls 74, 76 serve to enclose the transverse extent ofthe molten lead thereat. Following their arcuate shape, the workingsurfaces 80, 82 span from respective exits 68, 72 to the egress end 92,and therealong the working surfaces 80, 82 confront the respective outersurfaces of the rollers 30, 32 across the respective clearances. Theextent of the confrontation and the extent of the maintained clearancesprovides an expansive scope of contact between the molten lead androllers 30, 32 compared to previously-known casting machines. The moltenlead is hence more progressively cooled and hardened as it moves fromthe exits 68, 72 and to the egress end 92 and downstream thereof

The nozzle 28 is designed and constructed as a separate and modular unitin the lead strip caster 10 that can be readily assembled anddisassembled in the lead strip caster 10. In this way, the lead stripcaster 10 can be equipped with an interchangeable nozzle component.Different nozzles of different designs and constructions can beexchanged in the lead strip caster 10 to produce continuous lead stripsof various widths and thicknesses, as desired. For instance, the widthof the produced continuous lead strip can vary among different nozzledesigns and constructions with different transverse lengths between thefirst and second side walls 74, 76. In addition, the thickness of theproduced continuous lead strip can vary among different nozzle designsand constructions via one or more of the following measures: adjustmentof the sizes and dimensions of the passages 62, 64; adjustment of thesizes and dimensions of the clearances between the working surfaces 80,82 and outer surfaces of the rollers 30, 32; displacement of the forwardand rearward location of the egress end 92; and/or adjustment ofclearance between the outer surfaces of the rollers 30, 32.

Together with the nozzle 28, the first and second rollers 30, 32 work tobring the molten lead from its molten state to a hardened state readyfor further processing by the rolling mills 16. Referring generally toFIGS. 12 and 13, as described, when assembled in the lead strip caster10 the first roller 30 is situated at a first exterior side of thenozzle 28 where an arcuate section of a first outer surface 94 confrontsthe first working surface 80, and the second roller 32 is situated at asecond exterior side of the nozzle 28 where an arcuate section of asecond outer surface 96 confronts the second working surface 82. Thefirst and second rollers 30, 32 can have various designs andconstructions in different embodiments. As depicted in FIG. 12, in thisembodiment the rollers 30, 32 may have one or more grooves 98 at theirouter surfaces 94, 96 in order to augment traction established betweenthe molten and hardened lead and the rollers 30, 32. At their axiallyoutboard ends, the rollers 30, 32 have first and second axles 100, 102for coupling to the respective first and second drivers 34, 36 andpermitting rotation thereabout. The first and second drivers 34, 36 canbe motors that drive continuous rotation of the respective first andsecond rollers 30, 32 amid operation of the lead strip caster 10.Lastly, and as partially depicted in the sectioned view of FIG. 13, therollers 30, 32 can be equipped with a thermal construction 104 thatcirculates thermal fluid to manage and control the temperature of theouter surfaces 94, 96, as desired. In FIG. 13, thermal fluid circulatesthrough circulation veins that are represented and illustrated in thefigure as vertical bars that lack sectional pattern lines. In oneembodiment, the thermal construction 104 recirculates thermal fluid inthe form of coolant, such as water, through internal chambers definedwithin the rollers 30, 32. The outer surfaces 94, 96 are thereby cooled.In another embodiment, the thermal construction 104 recirculates heatedthermal fluid through the internal chambers. The outer surfaces 94, 96are thereby heated. During use of the lead strip caster 10, the streamsof molten lead leaving the exits 68, 72 come into direct contact withthe respective cooled or heated outer surfaces 94, 96 as the rollers 30,32 rotate. The streams of molten lead maintain that contact until afterthe streams merge and unite together downstream of the egress end 92.The contact with the outer surfaces 94, 96 serves to control thetemperature of the molten lead, as desired, such as progressivelycooling it into a hardened state. In this way, the rollers 30, 32 andtheir thermal constructions 104 can serve to help control thetemperature of the molten lead.

As described, the lead strip caster 10 is designed and constructed toexhibit a horizontal orientation. In other words, the ladle 26 andnozzle 28 are configured generally side-by-side relative to each otherwhereby molten lead flows and moves along a general horizontal andlateral course from the ladle's inlet 54 and ultimately to the nozzle'segress end 92. While the flow and movement of the molten lead may havelocalized departures from a strictly horizontal and lateral course—suchas when the molten lead passes over the partition wall 48 along the pathB—the general flow and movement is still principally horizontal andlateral, especially when contrasted with conventional casting machinesthat have a vertical configuration. In the vertical configurations,molten lead is fed vertically downward from an upwardly-located ladle toa downwardly-located set of rollers. Impurities and dross residing attop surfaces of molten lead pools in the ladles of verticalconfigurations can make their way to the sets of rollers, which causesdeformations and defects in the produced lead strip and ultimately inthe grids. The horizontal orientation of the lead strip caster 10 andthe nozzle 28 resolves these issues. Any impurities and dross residingat the top surface of the pool A remain thereat and are precluded frommaking their way to the nozzle 28 and, therefore, to the producedcontinuous lead strip. The ladle's outlet 56 is located at the bottomsection of the ladle 26 and is directed horizontally and laterally tothe nozzle 28, as perhaps demonstrated best in FIG. 5. This location anddirection frustrates, if not altogether precludes, the migration of leadimpurities and dross to the nozzle 28. Furthermore, the flow andmovement of molten lead through the nozzle 28 shields and safeguards themolten lead from the atmosphere, hence averting dross formation at thenozzle 28.

As shown in FIG. 14, a delivery system 100 may provide molten lead froma furnace directly to the nozzle 28 of the lead strip caster 10 withoutexposing the molten lead to the atmosphere to at least substantiallypreclude migration of lead impurities and dross to the nozzle. Thesupply system 100 may include a molten lead pump assembly 102 which inoperation supplies molten lead to the nozzle 28 through a shoe 104 anddesirably through a fluid flow straightener 106 received between theshoe and the nozzle. The pump assembly 102 may be have a centrifugalpump 108 with an inlet 110 and an outlet 112 submergible in a pool ofmolten lead in a pot of a lead melting furnace 14 or in a holding well(not shown) of molten lead transferred from a furnace 14. The pump 108may be driven by an electric motor through a shaft connected to animpeller with the shaft desirably received in a ceramic sleeve 114.Desirably the pump inlet 110 may be positioned in the range of about onequarter to three quarters of the vertical height or extent of the poolof molten lead in the furnace pot or holding well. Typically, the pumpassembly may deliver liquid lead to the inlet 110 of the shoe 106 at apressure in the range of 30 to 40 psi gauge and at a flow rate of 400 to600 lbs. of molten lead per minute. A suitable molten liquid leadtransfer pump assembly is commercially available from WirtzManufacturing Company of Port Huron, Mich., USA. A suitable transferpump assembly is also disclosed in U.S. Pat. No. 7,507,367 thedisclosure of which is incorporated herein by reference. In use the pumpassembly 102 supplies an excess quantity of liquid lead to an inlet 116(FIG. 17) of the shoe 104 through a conduit 118 and excess liquid leadis returned from an outlet 120 of the shoe through a conduit 122 to thefurnace pot or holding well. If needed, these conduits may be thermallyinsulated and if needed equipped with heaters such as electric heatersto ensure that in use the lead remains in a liquid state as it flowsthrough the conduits.

As shown in FIGS. 17 and 18 the shoe 104 has a body 124 which may begenerally rectangular, a longitudinally extending lead outlet slot 126opening into a front face 128 of the body and communicating at generallyopposed ends with inlet and outlet connectors 116, 120 through inlet andoutlet passages 130, 132 in the body. To maintain lead in the shoe in aliquid state, electric cartridge or rod heaters may be received in boresor passages 134 extending longitudinally through the body, laterallyspaced from each other and in heat transfer relationship with the leadoutlet slot and its associated inlet and outlet passages. These heaterelements may be thermostatically controlled to maintain the liquid leadin the shoe at a desired temperature range such as about 700 to 900degrees Fahrenheit. In assembly the outlet slot of the shoe communicateswith the nozzle 28 flow passages 62 and 64 at their entrances or inlets66 and 70, desirably through the fluid flow straightener 106.

As shown in FIGS. 19 and 20 desirably the flow straightener 106 may bein the form of a generally rectangular body 136 with a plurality ofspaced apart and generally parallel passages or bores 138 extendingtherethrough. These passages may be arranged in a generally honeycombpattern with alternating transverse rows of an odd and even number ofgenerally parallel spaced apart passages such as 4 and 5 passagesrespectively. Collectively, the passages 138 may desirably correspondwith the longitudinal extent and transverse width of the opening of thelead outlet slot 126 through the front face 128 of the shoe. As shown inFIG. 20, typically each passage 138 has a diameter in the range of about0.060 to 0.180 of an inch. Desirably the longitudinal and transverseextent of the outlet slot of the shoe and collectively the passages ofthe flow straightener may correspond with and span the perimeter of thecombined entrances 66 and 70 of the passages 62 and 64 of the nozzle 28.

In assembly the shoe 104 and the fluid flow straightener 106 desirablyhave a sealing gasket 140 between them, and may be aligned with andattached to the entrance end 78 of the nozzle 28 by suitable fastenerssuch as cap screws, bolts, or the like.

In use the pump assembly 102 supplies an excess quantity of molten leadunder pressure to the inlet 116 of the shoe 104 and some of this liquidlead flows through the flow straightener 106 and into and through thenozzle passages 62 and 64 and into contact with the corotating rollers30 and 32 upstream of the nip thereof to produce a cooled and hardenedor solid state continuous solid lead strip which downstream of therollers may be further processed by the rolling mills 16, trimmer 18,etc.

This molten lead delivery system 100 is believed to have the significantpractical advantages of shielding and isolating the molten lead from theatmosphere, and virtually, if not completely, eliminating impurities anddross from the liquid lead supplied to the nozzle 28 and thus, avoidingdeformation and defects which might otherwise be produced in the solidlead strip and ultimately battery grids made from the continuous solidlead strip.

While depicted and described for utilization in a horizontal orientationand configuration, the nozzle 28 could be equipped in a lead stripcaster exhibiting a vertical configuration. Moreover, whether in ahorizontal or vertical configuration, the nozzle 28 could be employed ina lead strip caster that need not necessarily include a ladle, andinstead could receive molten lead from other types of molten leaddelivery devices and systems that lack ladles such as molten leadfeed-lines.

While the forms of the invention herein disclosed constitute exemplaryforms and embodiments, many others are possible. It is not intendedherein to mention all the possible equivalent forms or ramifications ofthe invention. The terms used herein are merely descriptive, rather thanlimiting, and various changes may be made without departing from thespirit or scope of the invention.

1. A lead strip caster for battery plate grids, the caster comprising: asupply having an inlet to receive molten lead and having an outlet; anozzle having a passage that communicates with the outlet of the supplyto receive molten lead from the supply; a first roller situated at afirst exterior side of the nozzle, the first roller is rotatable and hasa first outer surface; and a second roller situated at a second exteriorside of the nozzle, the second roller is corotatable with the firstroller and the second roller has a second outer surface; wherein, duringuse of the lead strip caster, molten lead exiting the passage of thenozzle comes into contact with the first outer surface of the firstroller and comes into contact with the second outer surface of thesecond roller, the molten lead hardening as it moves downstream of thepassage in contact with the first and second outer surfaces.
 2. The leadstrip caster of claim 1, wherein the supply comprises a ladle and theladle and the nozzle exhibit a generally horizontal orientation relativeto each other.
 3. The lead strip caster of claim 1, wherein, from theoutlet of the supply and downstream to exiting the passage of thenozzle, molten lead flows along a generally lateral course.
 4. The leadstrip caster of claim 1, wherein the supply comprises a ladle and theinlet is an inlet of the ladle located at a bottom section of the ladle,and the outlet is an outlet of the ladle located at the bottom sectionof the ladle.
 5. The lead strip caster of claim 1, wherein the supplycomprises a ladle with a partition wall at an interior of the ladle thatdivides the interior into a first interior compartment and a secondinterior compartment, an inlet of the ladle feeding molten lead to thefirst interior compartment and an outlet of the ladle receiving moltenlead at the second interior compartment.
 6. The lead strip caster ofclaim 1, wherein the passage of the nozzle includes a first passage thatcommunicates with the outlet of the supply to receive molten lead fromthe supply, and includes a second passage that communicates with theoutlet of the supply to receive molten lead from the supply.
 7. The leadstrip caster of claim 6, wherein a first flow straightener is disposedin the first passage to receive molten lead moving through the firstpassage, and a second flow straightener is disposed in the secondpassage to receive molten lead moving through the second passage.
 8. Thelead strip caster of claim 6, wherein the nozzle has a first exteriorworking surface and has a second exterior working surface, the firstouter surface of the first roller confronting the first exterior workingsurface, and the second outer surface of the second roller confrontingthe second exterior working surface.
 9. The lead strip caster of claim8, wherein a first exit of the first passage delivers molten leadbetween the first exterior working surface of the nozzle and the firstouter surface of the first roller, and a second exit of the secondpassage delivers molten lead between the second exterior working surfaceof the nozzle and the second outer surface of the second roller.
 10. Thelead strip caster of claim 9, wherein molten lead delivered via thefirst exit of the first passage moves downstream of the first exittoward an egress end of the nozzle, molten lead delivered via the secondexit of the second passage moves downstream of the second exit towardthe egress end of the nozzle, and the molten lead delivered via thefirst exit and the molten lead delivered via the second exit mergetogether downstream of the egress end and between the first outersurface of the first roller and the second outer surface of the secondroller.
 11. The lead strip caster of claim 8, wherein the first andsecond exterior working surfaces are generally arcuately-shaped, thefirst outer surface of the first roller is shaped complementary to thefirst exterior working surface and nests therewith with a clearancemaintained therebetween to accept delivery of molten lead, and thesecond outer surface of the second roller is shaped complementary to thesecond exterior working surface and nests therewith with a clearancemaintained therebetween to accept delivery of molten lead.
 12. The leadstrip caster of claim 1, wherein the nozzle includes a plurality ofheaters carried by the nozzle to generate heat within the nozzle. 13.The lead strip caster of claim 1, wherein at least one of the firstroller or second roller is equipped with a thermal construction in whichthermal fluid circulates therein in order to cool or heat the outersurface of the first roller, or the outer surface of the second roller,or the outer surface of both the first and second rollers.
 14. The leadstrip caster of claim 1 wherein the supply comprises a pump having theinlet to receive molten lead and the outlet, the inlet configured to besubmerged in molten lead; a shoe having an elongate outlet slotcommunicating with the passage of the nozzle, an inlet communicating theslot with the outlet of the pump and an outlet communicating with theslot; and wherein during use of the lead strip caster, the pump suppliesto the inlet of the shoe an excess quantity of molten lead some of whichflows through the outlet slot into and through the passage of the nozzleand the rest of the excess molten lead flows through the outlet of theshoe.
 15. The lead strip caster of claim 14 which also comprises a fluidflow straightener communicating with the outlet slot of the shoe and thepassage of the nozzle.
 16. The lead strip caster of claim 14 wherein themolten lead supplied by the pump from its inlet through the shoe and tothe passage of the nozzle does not contact the exterior atmosphere. 17.The lead strip caster of claim 14 wherein from the outlet slot of theshoe and downstream to exiting the passage of the nozzle the molten leadflows along a path with a cross section perpendicular to the directionof flow and this cross section is horizontally longitudinally elongate.18. The lead strip caster of claim 14, wherein the nozzle has a firstexterior working surface and has a second exterior working surface, thefirst outer surface of the first roller confronting the first exteriorworking surface, and the second outer surface of the second rollerconfronting the second exterior working surface.
 19. The lead stripcaster of claim 18, wherein the first and second exterior workingsurfaces are generally arcuately-shaped, the first outer surface of thefirst roller is shaped complementary to the first exterior workingsurface and nests therewith with a clearance maintained therebetween toaccept delivery of molten lead, and the second outer surface of thesecond roller is shaped complementary to the second exterior workingsurface and nests therewith with a clearance maintained therebetween toaccept delivery of molten lead.
 20. A lead strip caster nozzlecomprising: a first passage receiving molten lead; a second passagereceiving molten lead; a first exterior working surface confronting afirst roller outer surface; a second exterior working surfaceconfronting a second roller outer surface; and wherein, during use ofthe lead strip caster nozzle, molten lead exiting the first passage isdelivered to the first exterior working surface, and molten lead exitingthe second passage is delivered to the second exterior working surface.21. The lead strip caster nozzle of claim 20, wherein the first passageand second passage are routed through the nozzle and generally exhibit amirror image with respect to each other, the first passage having atleast one linear section along its extent, and the second passage havingat least one linear section along its extent.
 22. The lead strip casternozzle of claim 20, wherein the first exterior working surface has agenerally arcuate profile, the second exterior working surface has agenerally arcuate profile, and molten lead delivered to the firstexterior working surface and molten lead delivered to the secondexterior working surface merge together downstream of an egress end ofthe lead strip caster nozzle.
 23. The lead strip caster nozzle of claim20, further comprising a first flow straightener disposed in the firstpassage to receive molten lead moving through the first passage, and asecond flow straightener disposed in the second passage to receivemolten lead moving through the second passage.
 24. A lead strip casterfor battery plate grids, the caster comprising: a nozzle having a firstpassage for flow of molten lead and having a second passage for flow ofmolten lead, and the nozzle having a first exterior working surface anda second exterior working surface; a first roller having a first outersurface that confronts the first exterior working surface; and a secondroller having a second outer surface that confronts the second exteriorworking surface; wherein, during use of the lead strip caster, moltenlead exiting the first passage of the nozzle is delivered to the firstexterior working surface and comes into contact with the first outersurface of the first roller, and molten lead exiting the second passageof the nozzle is delivered to the second exterior working surface andcomes into contact with the second outer surface of the second roller.25. The lead strip caster of claim 24, wherein the first and secondexterior working surfaces are generally arcuately-shaped, the firstouter surface of the first roller is shaped complementary to the firstexterior working surface and nests therewith with a clearance maintainedtherebetween to accept delivery of molten lead, and the second outersurface of the second roller is shaped complementary to the secondexterior working surface and nests therewith with a clearance maintainedtherebetween to accept delivery of molten lead.
 26. The lead stripcaster of claim 24, which also comprises a pump having an inlet toreceive molten lead and an outlet; a shoe having an elongate outlet slotcommunicating with the first and second flow passages of the nozzle, aninlet communicating the slot with the outlet of the pump and an outletcommunicating with the slot; and wherein during use of the lead stripcaster, the pump supplies to the inlet of the shoe an excess quantity ofmolten lead some of which flows through the elongate outlet slot intoand through the first and second passages of the nozzle and the rest ofthe excess molten lead flows through the outlet of the shoe.
 27. Thelead strip caster of claim 26 wherein the molten lead supplied by thepump from its inlet through the shoe and to the passage of the nozzledoes not contact the exterior atmosphere.